A power supply circuit of this type is known from European Patent Application EP-A 380033. This known power supply circuit has a pulse width modulation control in which the control circuit receives two input signals, i.e. a first input signal for determining the starting moment of a new pulse and a second input signal for receiving a signal related to the output voltage.
This known power supply circuit has the drawback that it does not operate efficiently, while the transformer may become saturated.